[The synthesis of triterpenic amides based on 2,3-seco-1-cyano-19beta,28-epoxy-18alpha-olean-3-oic acid].

Novel 2,3-seco-triterpenic amides were prepared by the interaction of the chloride of 2,3-seco-l-cyano-19beta,28-epoxy-18alpha-oleane-3-oic acid with primary amines and synthetic and biogenic amino acids. A cytotoxic triterpenic conjugate with a residue of the ethyl ester of beta-alanine was found among the synthesized nitrogen-containing derivatives. Treatment with this conjugate in a concentration of 100 muM resulted in the 45.5% survival of melanoma cells in the medium.

[New approaches to search for antitumoral compounds].

The authors discuss the present-day state of search for antitumoral compounds at Blokhin Russian Oncological Research Center and promising approaches including computer technologies as means of search for new anticancerous targets and drugs.

Selective antitumor activity of lymphokine-activated killer cells in vitro.

We compared cytotoxic activity of blood mononuclear leukocytes from healthy donors and lymphokine-activated killer cells generated from them towards tumor and normal cells. Lymphokine-activated killer cells exhibited higher (in comparison with blood mononuclear leukocytes) killer activity towards tumor cells. Lymphokine-activated cells and mononuclear leukocytes had no lytic effect on non-transformed eukaryotic cells. Hence, we demonstrated selective cytotoxic activity of effector cells (lymphokine-activated killers) towards tumor cells of different origin (but not normal cells).

Combined effect of cisplatin and lymphokine-activated killer cells on A549 cells of non-small cell lung cancer.

We studied the ability of lymphokine-activated killer cells to lyse A549 human non-small cell lung cancer cells after preincubation with cisplatin. Lymphokine-activated killer cells obtained after incubation of human blood lymphocytes with interleukin-2 were characterized by high expression of natural killer cell antigens and activation molecules. Lymphokine-activated killer cells produced potent cytotoxic effect on intact A549 cells and lysed tumor cells survived after treatment with cisplatin in concentrations of IC50 and IC30. Cisplatin in noncytotoxic concentrations did not increase lytic activity of lymphokine-activated killer cells.

[Synthesis and antitumor activity of cyclopropane derivatives of betulinic and betulonic acids].

New cyclopropane derivatives of betulin were synthesized by attachment of dichlorocarbenes or dibromocarbenes to the double bond of betulin diacetate, followed by the deprotection of hydroxyl groups. The betulin cyclopropane derivative was obtained from 20,29-dihydro-20,29-dichloromethylenebetulin by treatment with lithium in tert-butanol. These compounds were converted into the corresponding derivatives of betulonic acid by oxidation with chromium trioxide. The reduction of oxo group with sodium borohydride led to the corresponding derivatives of betulinic acid. 20,29-Dihydro-20,29-dichloromethylenebetulinic acid proved to be the most cytotoxic toward human melanoma of the Colo 38 and Bro lines and human ovarian carcinoma of the CaOv line (IC50 10 microM). 20,29-Dihydro-20,29-dibromomethylenebetulinic acid inhibited the growth of the Bro melanoma cell line and the CaOv carcinoma cell line practically by 50% at a concentration of 10 microM. The other derivatives of betulinic and betulonic acids were active toward all of the three cancer cell lines at concentrations higher than 10 microM. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2005, vol. 31, no. 3; see also http://www.maik.ru.

[Epimerization of hydroxyl group in the lupan series of triterpenes]. / Epimerizatsiia gidroksil'noi gruppy v triterpenakh lupanovogo riada.

Two methods of obtaining of 3 alpha-betulinic acid and related compounds from their 3 beta-epimers were studied: the reaction of bimolecular substitution and the stereoselective reduction of 3-ketoderivatives. The substitution of acyloxy by formyloxy group in 3-O-tosyllupeol or of the betulin hydroxyl by benzoyloxy group resulted only in delta 2, 3-elimination products, with none of the expected products of bimolecular substitution being found. The catalytic hydrogenation of betulonic acid over Raney nickel resulted only in reduction of the isopropenyl double bond, whereas the use of 5% Ru/C gave a 60:40 mixture of epimers of dihydrobetulinic acid. Practically the same mixture of betulinic acid epimers was obtained when reducing betulonic acid with L-Selectride. The cytotoxic activity of 3 alpha-betulinic acid increased toward melanoma Bro cells and decreased toward melanoma MS cells.

[A novel immunoregulating hexapeptide with antineoplastic effect]. / Novyi immunoreguliatornyi geksapeptid s protivoopukholevym deistviem.

A synthesized analog of myelopeptide HP-2-->M[symbol: see text]-2 (Leu-Val-Val-Tyr-Pro-Trp) caused a significant (60-80%) and prolonged inhibition of s.c. grafted tumors P388, Ca-755, B-16 and sarcoma 180 in isogenic mice but did not affect the growth of tumor B-16 in nude mice. Nor did it influence proliferative activity or viability of cultured human tumor cells. The best results were obtained with s.c. injections of 0.5-2 mg/kg HP-2-->M[symbol: see text]-2, twice or trice a day, at 96 hr intervals. No symptoms of severe poisoning were registered at doses of HP-2-->M[symbol: see text]-2 100 times the therapeutic one. A pharmacokinetic study in mice revealed prolonged circulation of HP-2-->M[symbol: see text]-2 in blood and a high affinity for the bone marrow (t 1/2 (130.1 hr and 431.6 hr, respectively). HP-2-->M[symbol: see text]-2 restored in vitro the ascites P388-suppressed cytotoxicity of murine T-lymphocytes. HP-2-->M[symbol: see text]-2 is regarded as a candidate for clinical studies of its potential of immunocorrection in cancer patients suffering T-lymphocyte immunity disturbances.

[Results of cooperation of Experimental and Clinical Chemotherapy, N. N. Blokhin Center for Oncology Research, Russian Academy of Medical Sciences (1952-2000)]. / Itogi sotrudnichestva éksperimental'nykh i klinicheskikh otdelov khimioterapii RONTS im. N. N. Blokhina RAMN (1952-2000 gg.).

Milestones of the Russian antitumor chemotherapy development inseparably associated with the names of N.N. Blokhin, L.F. Larionov and V.I. Astrakhan are reviewed. Since the early 50s of the last century, more than 7,000 generic and synthetic compounds have been studied by the three generations of chemotherapy researchers. 17 antitumor drugs have been developed and passed for clinical trials, 11 of them have been or still are being used in clinic.

[Synthesis and biological properties of 3,5-cyclophosphates- and -amidophosphates of 1,2-O-alkylydene-6-deoxy-6-halogeno-alpha -D-glucofuranoses]. / Sintez i biologicheskie svoistva 3,5-tsiklofosfatov i amidofosfatov 6-galoid-6-dezoksi-1,2-O-alkiliden-alpha-D-gliukofuranoz.

3,5-Cyclic phosphates and phosphoramides of 6-halogenated glucofuranoses were synthesized via interaction of 3,5,6-bicyclophosphites of 1,2-O-alkylidene-alpha-D-glucofuranoses with halogens (followed by treatment with nucleophilic reagents) and N-chloroamines. 3,5-Cyclic trans-dibutylphosphoramides of 6-chloro-6-deoxy-1,2-O-isopropylidene- and 6-chloro-6-deoxy-(R)-(2,2,2)-trichloroethylidene)-alpha-D-glucofuranoses were shown to possess antiproliferative activity against CaOv human ovarian carcinoma cells in vitro (CE50 of approximately 10(-5) M). Cyclic trans-dibutylphosphoramide of 6-chloro-6-deoxy-1,2,-O-isopropylidene-alpha-D-glucofuranose also displayed marked antitumor effect on P-388 transplantable murine leukemia in vivo (the maximum increase in life span of 100% was reached at the quintuple injection of 100 mg/kg daily).

Antitumor activity of conjugates of the oncofetal protein alpha-fetoprotein and phthalocyanines in vitro.

The several conjugates of aluminium and cobalt complexes of phthalocyanines with human alpha-fetoprotein have been synthesized. Their cytotoxic activity against tumor cells and human peripheral blood lymphocytes was studied. The experimental data demonstrate that the cytotoxic activity of alpha-fetoprotein-phthalocyanine conjugates against three types of tumor cells of various origin is much higher (for aluminium and cobalt complexes more than 1000 and 50 times, respectively) in comparison with phthalocyanines themselves. The application of phthalocyanines as conjugates with alpha-fetoprotein makes it possible to markedly enhance the selective toxicity of phthalocyanines against human tumor cells.

Antitumor activity of conjugates of the oncofetal protein alpha-fetoprotein and phthalocyanines in vitro.

The several conjugates of aluminium and cobalt complexes of phthalocyanines with human alpha-fetoprotein have been synthesized. Their cytotoxic activity against tumor cells and human peripheral blood lymphocytes was studied. The experimental data demonstrate that the cytotoxic activity of alpha-fetoprotein-phthalocyanine conjugates against three types of tumor cells of various origin is much higher (for aluminium and cobalt complexes more than 1000 and 50 times, respectively) in comparison with phthalocyanines themselves. The application of phthalocyanines as conjugates with alpha-fetoprotein makes it possible to markedly enhance the selective toxicity of phthalocyanines against human tumor cells.

[Effect of anti-tumor agents cisplatin and cycloplatam on membrane protein kinase C activity in murine T-lymphocytes]. / Vliianie protivoopukholevykh preparatov tsisplatina i tsikloplatama na aktivnost' membrannoi proteinkinazy s T-limfotsitov myshi.

The effect of cisplatin and the new drug cycloplatam (amine (cyclopentylamine)-S-(-)-malatoplatinum (II)) on protein kinase C (PKC) activity and Ca(2+)-dependent binding of PKC to T lymphocytes membranes was studied in vivo and in vitro. At first, the effect of the drugs on PKC activity of intact and activated lymphocytes was studied in vivo. In 48 hours after intraperitoneal injection of mice with therapeutic doses of the drugs, PKC activity of intact lymphocytes was differentially affected. Cisplatin did not practically alter the enzyme activity, whereas cycloplatam inhibited the PKC activity by 37% versus control. In lymphocytes activated by mouse P-388 leukemia cells in vivo, the drugs caused almost complete suppression of PKC activity and Ca(2+)-dependent binding of the enzyme to the membranes. The drugs were effective in intact cells. After incubation of intact lymphocytes in vitro for 24 hours with cisplatin or cycloplatam (10(-5)M), PKC activity was increased 1.62- and 1.35-fold, respectively, versus control. Ca(2+)-dependent binding of the enzyme to the membranes was also increased 1.61- and 1.36-fold by cisplatin and cycloplatam, respectively. On the contrary, at 10(-4) M concentration under similar conditions, the drugs did not affect the PKC activity of the lymphocytes. Furthermore, cycloplatam, unlike cisplatin, reduced the PKC binding to cellular membranes by 31%. The mechanisms of the drugs effects on PKC activity are suggested. The data indicate that increase or decrease of PKC activity induced by the drugs cause stimulation or depression of functional activity of T lymphocytes, respectively. Thus, the membrane-bound PKC can play the key role in initiation and development of immunomodulatory effects of cisplatin and cycloplatam.

[The use of verapamil in tests for determining the drug resistance of leukemic blasts]. / Ispol'zovanie verapamila v testakh dlia opredeleniia lekarstvennoi ustoichivosti leikoznykh blastov.

To determine prognostically unfavourable groups of acute leukemia patients, the authors studied the in vitro accumulation of 3H-vincristine (Vcr) and adriamycin (ADR) as well as inclusion of 3H-cytosar (Ara-C) into marrow blast DNA from patients showing different effects of treatment. It was found resistant to induction chemotherapy increases with verapamil addition to culture medium (Vrp+ cells). ADR inclusion into Vrp+ cells was the same as that into Vrp- cells. The inclusion of 3H-Ara-C into S-phase cell DNA in the cells Vrp+ was 3 time that in the cells Vrp-. All the responders to cytosar treatment had Vrp- blasts. It is evident that evaluation of Vrp effect on 3H-Vcr accumulation under short-term culturing is able to indicate groups of patients with low probability of achieving complete remissions in response to standard regimens of Vcr, Ara-C and anthracyclines treatment.

Antiproliferative effect of complexes of platinum (II) with plasmanyl-(N-acyl)-ethanolamine, an inhibitor of protein kinase C.

Antiproliferative activities of combinations of semisynthetic plasmanyl-(N-acyl)-ethanolamine [PNAE(s)], an inhibitor of protein kinase C, with two antitumor complexes of platinum (II) [cisplatin and ammine(cyclopentylamine)-S-(-)-malatoplatinum (cycloplatam)] were investigated. The exposure of human melanoma BRO cells in culture simultaneously with cisplatin (1-10 microM) and PNAE(s) (100 microM-1 mM) in a molar ratio of 1/100 for 24 h induced a considerable decrease in the ability of these cells to incorporate [3H]thymidine into DNA. A considerable antiproliferative synergism of these agents was observed. The effect of cycloplatam/PNAE(s) combination in similar experiments was significantly different from cisplatin/PNAE(s), i.e. interaction of these agents was complex and synergism was not found.

[Biochemical indicators of anthracycline sensitivity of blast cells from patients with hemoblastoses]. / Biokhimicheskie pokazateli chuvstvitel'nosti k antratsiklinam blastnykh kletok bol'nykh gemoblastozami.

It was shown that accumulation of adriamycin (ADR) and its impact on DNA synthesis in the blast cells of patients with hemoblastosis studied under conditions of short-term incubation correlated with the antileukemic activity of anthracyclines. The combination of the two biochemical and pharmacological indices, i.e. the high levels of ADR accumulation and inhibition of DNA synthesis, is may useful in solving the problem on inclusion of the antibiotics to the schemes of combined chemotherapy of patients with hemoblastosis.

Inhibition of protein kinase C by semisynthetic phospholipid plasmanyl-(N-acyl)-ethanolamine, a nontoxic antitumor preparation.

Protein kinase C was extracted from mouse brain and partially purified by ion-exchange chromatography on a DEAE-cellulose column. Its activity was determined by incorporation of phosphate from [gamma-32P]ATP into histone H2b. The semisynthetic alkyl-phospholipid plasmanyl-(N-acyl)-ethanolamine (PNAEs) with selective antitumor activity inhibited the activity of the protein kinase in a cell-free system in the presence of phosphatidylserine, a protein kinase C activator. The inhibition was competitive with respect to phosphatidylserine, the inhibition constant being 40 microM.

Synergistic antiproliferative effect of cis-diammine-dichloroplatinum (II) and a new anticancer agent, plasmanyl-(N-acyl)-ethanolamine, an inhibitor of protein kinase C.

The action of a new anticancer agent, the semisynthetic alkyl-phospholipid plasmanyl-(N-acyl)-ethanolamine (sPNAE), namely 1-O-octadecyl-2-oleoyl-sn-glycero-3-phospho-(N-palmitoyl)-ethanolamine, on protein kinase C (PKC) was investigated, and it was found to inhibit in a dose-dependent manner PKC isolated from mouse brain. The inhibition was competitive with respect to phosphatidylserine (K(i) = 20 microM). Lyso-PNAE, a possible cell metabolite of sPNAE, also inhibited PKC. A two-site model was used to calculate the binding affinity and the number of binding sites for phorbol ester in a culture of human melanoma BRO cells. The values of Kd, the dissociation constant, were K'd = 0.5 nM and K"d = 72 nM, whereas the values of Bmax, the number of binding sites, were B'max = 4.6 x 10(4) sites cell-1, and B"max = 2.9 x 10(5) sites cell-1. sPNAE was able to reduce the affinity of BRO cells for phorbol ester with almost no changes in the number of binding sites: K'd = 1.6 nM, K"d = 557 nM, and B'max = 4 x 10(4), B"max = 1.9 x 10(5). These data suggest that sPNAE may inhibit PKC in intact cells. Since various inhibitors of PKC may enhance the antiproliferative activity of cis-diamminedichloroplatinum(II) (cis-DDP), we investigated the effect of the combination of sPNAE and cis-DDP on the proliferation of BRO cells. sPNAE synergistically enhanced the antiproliferative activity of cis-DDP.